Physical Sciences and Mathematics Commons^™

Comparison Of Positive Screening And Confimatory Results From Federally Mandated Drug Testing Of Urine, Mary M. Stuck

Community & Environmental Health Theses & Dissertations

The purpose of this study was to analyze the accuracy of FDA approved immunoassays for the detection of drug positive urine samples.

Federal civilian employees are tested under the strict protocol of the Department of Health and Human Services mandatory guidelines for federal workplace drug testing programs. The guidelines provide for a two instrument testing protocol for the analysis of urine samples. The first is an FDA approved immunoassay. Samples which test positive on this screening immunoassay are then submitted for confirmatory testing with the "gold standard" gas chromatography/mass spectrometry.

Agency monthly drug testing summaries, required under the DHHS guidelines …

Concentrations, Complexation And Speciation Of Total Dissolved Zinc In The Chesapeake Bay, Charles William Henry Iii

Chemistry & Biochemistry Theses & Dissertations

This is the first research to examine the horizontal, vertical, and temporal variability of total dissolved zinc, organic complexation of zinc, and zinc speciation in the Chesapeake Bay. Filtered (0.45μm) surface and bottom water samples were taken along the salinity gradient of the Chesapeake Bay in October 1993, March 1995, July 1995, and October 1995. Analysis by Differential Pulse Anodic Stripping Voltammetry (DP ASV) indicated that total dissolved zinc concentrations in the Bay ranged from 2.9 ± 0.7nM to 38.8 ± 2nM. Total zinc was highest at the northern end of the Bay (low salinity), approximately 10 times lower at …

Reactions Of Aqueous Chlorine With Alanylphenylalanine In Model Solutions And In A Wastewater, Thomas C. Fox

Chemistry & Biochemistry Theses & Dissertations

Model solutions of the dipeptide alanylphenylalanine were chlorinated to four different chlorine-to-amino nitrogen (Cl₂/Ala-Phe) mole ratios and analyzed by high performance liquid chromatography. At mole ratios ≤ 1, N-chloroalanylphenylalanine was the only major product. As the Cl₂/Ala-Phe mole ratio was increased to ≥ 2, N,N-dichloroalanylphenylalanine was the only major product. In model solutions (pH 7.0) the dichlorinated dipeptide decomposed (t_1/2= 4.1 hr) to form a stable N-chloroketimine, which has a half-life of 125 hours. This N-chloroketimine then decomposed to form phenylalanine.

To follow these reactions in a wastewater, alanyl-p-[ …

Petrochemical Analysis By Remote Fiber-Optic Raman Spectroscopy And Partial Least Squares Regression Analysis, Philip Edmund Flecher Jr.

Chemistry & Biochemistry Theses & Dissertations

A dispersive Raman system with charge coupled device (CCD) detection, distributed Bragg reflector (DBR) diode laser excitation, and a fiber optic probe has been developed for the rapid analysis of petrochemicals and fuels. Initially, mock petroleum fuels with analyte concentrations from 1.S - 16% were prepared and analyzed with the system. The inability of the original index guided diode laser to maintain a constant frequency during the mock petroleum analysis was a recurrent problem. The DBR laser was subsequently shown to have stability superior to index guided lasers, and was used in the remainder of the research.

Real gasoline samples …